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Nanogranite Inclusions: New Window into the Partial Melting of the Deep Earth´s Crust

Periodic Reporting for period 1 - NANOGRANITES (Nanogranite Inclusions: New Window into the Partial Melting of the Deep Earth´s Crust)

Reporting period: 2016-11-01 to 2018-10-31

Partial melting is a key process in the evolution and compositional differentiation of the Earth and, in particular, the Earth´s Continental Crust. Knowledge about these processes is hampered by the absence of precise information on the composition of primary natural melts. The main goal of this project is to provide the compositions of primary crustal melts through the experimental study of nanogranitoids, a new approached recently proposed and developed by Prof. Cesare and his research team at the Università di Padova (UNIPD), Italy.

This study corresponds to basic science, which is the foundation of all scientific theories and the basis for applied science. Crustal anatexis is the process that mobilizes and concentrates many of the basic elements human race use to manufacture their devices. Knowledge about this process will improve our knowledge about the geochemical cycle of these elements, and improve our techniques to detect and extract them.

The overall objectives of this project are:
Objective 1: To provide the composition of primary crustal melts by remelting and analyzing nanogranites hosted in peritectic minerals from migmatites and granulites.
Objective 2: To investigate the mechanisms of anatexis, by conducting melting experiments using the migmatites hosting the studied nanogranites, and by comparing the compositions of experimental glasses and remelted nanogranites.
Objective 3: To determine the implications of the compositions of remelted nanogranites on the generation and differentiation of the continental crust.

Conclusions of the action:
This project was designed to be conducted in three years, but has been terminated in month 8th of the second year, because I have obtained a permanent position at the Instituto Andaluz de Ciencias de la Tierra of Spain (IACT). I have conducted most of the proposed experiments, I have analyzed most of the conducted experiments, and I have used all of the analytical techniques proposed in the project. As major conclusions, regarding objective 1, I have found that the composition of the studied nanogranites is leucogranitic and shows variable proportions of H2O and CO2. Major conclusions/results involving objective 2 are being discussed now. Major conclusions/results involving objective 3 will be available after the conduction of geochemical and thermodynamic modeling, which will be done in the near future. The first results of this project consist of 1 article in a first-class journal, 1 article under review, 2 oral talks, 1 poster and 3 abstracts presented in international meetings, and 3 talks delivered at Australian National University (ANU), Australia.
I have sampled rocks during 1 field study, have conducted most of the proposed experiments, have studied starting rocks and the conducted experiments using all of the proposed analytical techniques, have attended 2 international meetings and delivered oral talks at ANU, and published articles in international journals exposing part of our results. There is still some work to be conducted (corresponding to the third year of the project), and results to be discussed and published.

The actions performed include:

I did 1 field trip to the Betic Cordillera (S Spain), to collect additional samples of the studied nanogranitoids. The result is the collection of new and better quality samples.

I met with collaborators in Granada (Spain) and Bern (Switzerland). The result involves discussion to provide sound interpretations of our experimental results.

I attended 2 international meetings, New Orleans (AGU 2017) and a Granites2017@Benalla (Benalla). The result is the dissemination of results and discussion with leading researchers in the field.

I studied thin sections from rocks with nanogranitoids using all proposed techniques. The result is a precise characterization of the host rocks and nanogranitoids.

I conducted 60 Piston Cylinder experiments. The result is the remelting of nanogranites and host rocks.

I studied experimental products using all proposed techniques. The result is a precise characterization of remelted nanogranites and host rocks.

I published 1 article in a first-class journal and 3 abstracts in international meetings; another article is under review. The result is the dissemination of this work.

Other actions involve the editorial work for 2 international journals (American Mineralogist, Geosciences), review of manuscript as external reviewer for several international journals (5 to 10 article per year), co-advice 1 PhD student (Università di Padova) and participate in the Committee Thesis Defense of a PhD (Universite du Quebec a Chicoutimi, Canada) and a Honors thesis (ANU).

Overview of the results and their exploitation and dissemination:
Even if I conducted 20 out of the 36 months planned, most of the key planned actions have been conducted, and dissemination of results has been appropriate and according to the plan.
Objective 1 has been achieved. I have refined the strategy for the experimental treatment of nanogranites, and have obtained the composition of the studied nanogranites. 1 article has been published, another is under review. More papers are being prepared.
Objective 2, planned to be developed during year 2, has been partially achieved, though a large number of meaningful experiments have been conducted and partially characterized. Papers are being prepared.
Objective 3, planned to be developed during the year 3, has not been achieved, Nevertheless, the data generated will be used to achieve this objective in the near future and associated papers will be prepared.
Objective 1: I have refined the strategy for the experimental treatment of nanogranitoids, which is by itself a brand new methodology recently develop by Prof. Cesare and coworkers. We have obtained new compositions of remelted nanogranitoids. The obtained analyses of H2O and CO2 in remelted nanogranitoids by NanoSIMS are some of the few currently available. The information about crustal anatexis from the perspective of nanogranitoids is totally innovative.
Objective 2: results associated with this objective are still being analyzed and discussed. I expect to provide innovative information on the mechanisms of crustal anatexis in all studied geodynamic settings.
Objective 3: actions associated with the third objective have not been conducted. They will be conducted in the near future and I expect to provide innovative information on the genesis and evolution of the continental crust.

I expect that between 5-10 more articles, related with results obtained in this project, will be published in first class international journals within the next 2-3 years.

The most evident impact of this project is that it has provided the environment for the professional maturation and consolidation of the researcher. As a consequence the researcher has obtained a permanent position in Europe, at the IACT. This is the reason for the termination of the Grant Agreement before completing the action. This, together with the new knowledge, skills and connections acquired by the researcher during the implementation of 2/3 of the project, and the on going collaborations with the Beneficiary Institution, UNIPD, should increase the excellence and competitiveness of science in the European Research Area, should help Europe in being one of the leaders in this research field, and should help attracting high-quality researchers in this and related fields to Europe.